Drafting instrument.



J. H. CLARK. DRAPTING INSTRUMENT. APPLIGATION FILED Nov. 2, 1911.

Patented Sept. 29, 1914.

Fig. 3.

THE KORRIS PEI :RS CO., ruomurua. WASHINGTON. D. C.

UNITED STATES PATENT OFFICE.

JAMES H. CLARK, or FLINT, MICHIGAN. y

DRAFTING INSTRUMENT.

1,112,264. Specification of letters Patent Patented Sept. 29, 1914. Application filed November 2, 1911. Serial No. 658,124.

To all whom it may concern: a apertured to receive the squared portion- Be it known that I, JAMES H. CLARK, a 12 of the bar and is vertically apertured citizen of the United States, residing at to receive an adjusting screw16 which acts Flint, in the county of Genesee and State of to clamp the legupon the arm in adjusted so ([ichigan, have invented new and useful osition. It will be noticed that as the Improvements in Drafting Instruments, of, egs 2 and 3 are drawn together, the bar which the following is a specification. 10 will drop upon the body 1 and the This invention relates to drafting instrupoints 4 and will always be maintained ments and more particularly to that type approximately collinear. j known as dividers. For setting the instrument, we will as- The object of the invention is provision sume, for instance, that we have a round of a simple and eflicient device of this charbar, as shown in Fig. 5 at 17, and it is deacter whereby the points for a true ellipse. sired to obtain an ellipse represented after may be readily obtained or whereby the the bar has been sawed off atthe desired device may be used as a simple divider. angle. Take the radius 18, which is equal Further objects of this invention will apto one half of the diameter of the bar, swing pear as the following specific description is a line 19 from the center 20 to a point of read in connection with the accompanying intersection with the line representing the drawing, which forms a part of this appliform desired, the point of intersection becation, and in which ing indicated at 21. The instrument is now Figure 1 is a side elevation. Fig. 2 is a set with the point A at the junction of the top plan view. Fig. 3 is an edge elevation. bottom line of the bar to the diagonal cut- Fig. 4. is a side elevation with the adjustting line and the point B is set on the point able leg reversed. Fig. 5 is a diagrammatic 21 while the point C of the leg'14c is set 8 view illustrating the application of the deupon the point 20. We now have the invice. strument set so that the distance between Referring more particularly to the drawthe points A and C and the distance being, 1 represents the ordinary knurled h'antween the points B and C are equal to one dle of the divider body 1 from which dihalf of the major and minor aXe-s respec- '85 verge the spring legs 2 and 3, both of which tively. In order to obtain the points for a are provided with an ordinary needle point trueellipse, the lines representing the minor 4:. Intermediate the length of the legs suitand major axes should cross each other at able bearings 5 are journaled therein and Then by taking the instrument and these hearings are provided with transverse keeping the points A and B on the lines 9 screw threaded apertures adapted to receive representing theminor and major axes re the right and left hand screw 6,'the right spectively, the point C will produce the hand portion of the screw being threaded true location for the points of an ellipse into the bearing of the leg 2, while the left since the distance between the points B and hand portion of the screw is threaded into C and A and C are equal to the semi-minor 5 the bearing of the leg 3. A knurled disk and the semi-major axes of a true ellipse. 7 is secured to the screw for operating the It will be noticed that the leg 14 is adsame so as to spread or draw the legs to justable upon the squared portion of the gether, as desired, bar 10 and that it is also reversible to obtain Bearings 5 in each leg are provided with the polnts for an extremely small ellipse or laterally projecting studs which are ena larger ellipse than a certain length bar gage in the bifurcated lower ends of conwould permit providing the leg was straight necting links 8. The upper ends of each thus increasing the range of the instrument. are similarly bifurcated so as to pivotally What is claimed is: receive laterally extending studs 9 carried 1 A drawing instrument of the class deby a parallel bar 10 which is apertured to scrlbed comprising abody having a handle, receive the body 1*, as shown at 11. Bea pair of yieldable legs provided on said yond the connection of the left hand link body and having pointed free ends, means with the bar 10, the bar is squared and by which said legs may be flexed laterally slidably mounted thereon is a head 13 of to effect relative adjustment of the points 11 a leg 14 which is provided, as usual, with thereof, a third leg having its free end the point 15. The head 13 is transversely pointed, means for mounting the last-named scribed comprising a body scribed comprising a a pair of yieldable legs provided upon said by which said legs may be flexed laterally to effect relative adjustment of the points leg movably upon the body, associating the said mounting means for the third leg with the first-named legs for maintaining the points of all the legs in substantial collinearity irrespective of the relative adjustment of the first-named legs.

2. A drawing instrument of the class dehaving a handle, a pair of yieldable legs provided on said body and having pointed free ends, means thereof, a third leg having its free end pointed, a member mounted for longitudinal movement upon the said body for connecting the third leg therewith the said third leg being adapted to be adjusted laterally with respect to the first-named legs, means for securing the third leg in laterally adjusted position upon the said member, and means for maintaining the points of all the legs in substantial collinearity irrespective of the relative adjustment of the firstnamed legs. i

3. A drawing instrument of the class described comprising a body having a handle, a pair of yieldable legs provided upon said body and'having pointed free ends, means by which said legs may be flexed laterally to effect relative adjustment of the points thereof, a laterally projecting bar mounted upon the body for longitudinal movement thereon, a third'leg attached to the said bar and having a pointed free end disposed in substantial collinearity with the points ot the first-named blades, and means operatively connecting the first-named legs with the said bar for maintaining the collinearity of the points of all the legs.

LA drawing instrument of the class debody having a handle,

body and having pointed free ends, means by which said legs may be tlexed laterally to effect relative adjustment of the points thereof, a laterally projecting bar mounted upon the body for longitudinal movement thereon, a third leg attached to the said bar and having a pointed free end disposed in substantial collinearity with the points of the first-named blades, and a pair of rigid and means body and having pivoted link members having corresponding ends thereof pivotally connected to the respective first-named legs and their opposite ends pivoted to the said bar at points spaced from each side of the body.

5. A drawing instrument of the class described comprising a body having a handle, a pair of yieldable legs provided upon said pointed free ends, means by which said legs may be flexed laterally to effect relative ad'ustment of the points thereof, a laterally projecting bar mounted upon the body for longitudinal movement thereon, a third leg attached to the said bar and having a pointed free end disposed in substantial collinearity with the points or the first-named blades, and a pair of rigid link members having corresponding ends vthereof pivotally connected to the respective ends to the said bar at points spaced from each side of the body, the said, link members being movable in a common plane with the said legs and bar.

6. A drawing instrument of the class described comprising a body having a handle, a pair of depending yieldable legs provided upon said body and having pointed free ends, means by which said legs may be flexed laterally to e'tlect relative adjustn'ient of the points thereof, a laterally projecting bar slidably mounted upon said body for longitudinal movement thereon, a third leg slidably mounted upon the said bar and having a pointed free end disposed substair tially in collinearity to the points of the first-named le s, means by which the third leg. may be secured in its dillerent longitudinally adjusted positions upon the said bar, and means operatively connecting the first-named legs with the bar for maintaining the approximate collinearity of the said. points throughout their range of adjustment.

In testimony whereof I ailix my signature in presence of two witnesses.

JAMES H. Cl'nillli.

first-named legs and their opposite Witnesses GRANT J. Brown,

BESSIE C. TUCKER.

Copies of this patent maybe obtained for five cents each, by addressing the Commissioner of Iatents.

Washington, D. G. 

